Refining lubricating oil with dichloroethyl ether



Nov. 23, 1937- c. c. BUCHLER ET AL 2,100,099

REFINING LUBRICATING OIL WITH DIGHLOROETHYL ETHER Filed March 10, 1952 Chiller fierz erze JtZZZ filtrate Collector wax recovery Et/zer Jazz CZzffo/d G flaclder vwhines 775. Hzye, .jr.

INVENTORS ATTORNEY Patented Nov. 23, 1937 UNITED STATES REFINING LUBRICATING OIL TH DI- CHLOROETHYL ETHEE Clifl'ord C. Buchler and James M. Page, Jr., Gas- Der, Wyo., assignors to Standard Oil Company, Chicago, 111., a corporation of Indiana Application March 10, 1932, Serial No. 597,890

15 Claims.

This invention-relates to refining lubricating oils and it pertains more particularly to the dewaxing and extraction thereof with dichlorethyl ether.

The object of the invention is to provide a method of dewaxing lubricating oil bymeans of a selective solvent which will dissolve practically all of the oil and which will not dissolve the petroleum waxes contained therein. A further 0 object is to provide a combined treatment of petroleum oil with dichlorethyl ether so that the wax may be removed from the oil prior to the separation of paramnic from naphthenic components. A further object is to provide an improved system whereby a blending agent may be mixed with dichlorethyl ether to eflect complete solution of the oil during the dewaxing treatment and whereby this blending agent may be distilled from the diluted oil to cause the separation of paraifinic oil from the dichlorethyl ether solution.

A further object is to decrease the cost of separating undesirable components from a lubricating oil and to provide a lubricating oil of improved properties. In practicing the invention we utilize a solvent, such as B. B dichlorethyl ether,

ClCHzCHzOCHzCHzCl This dichlorethyl ether is completely miscible with both oil and wax at temperatures of from 125-165 F., depending upon the. molecular weights of the oil and wax. When this mixture is cooled to about 100 F., the waxes are precipitated from the solution while the bulk of the 30 oil remains in the solution and a separation may therefore be effected. Our preferred method, however, is to dewax at temperatures below 0 FL, and in order that the oil may remain in solution atthese low temperatures we mix benzene with 0 the dichlorethyl ether. When the benzene is removed from the dewaxed oil the paraflinic and naphthenic components thereof may be readily separated by the dichlorethyl ether which remains admixed therewith.

The invention will be more clearly understood from the following detailed description and from the accompanying drawing which illustrates a preferred embodiment of our invention. The drawingtrepresents a diagrammatic plan of our improved system. We may utilize our invention in treating any wax-bearing oil, but in our preferred embodiment we will describe the method of dewaxing and extracting a Salt Creek motor base which has been treated with 2% pounds of 55 104%% sulfuric acid, said oil having a viscosity of about 75-78 seconds Saybolt at 210 F. When heavyoils are used it may be desirable to cut their viscosity by means of filter naphtha or other light hydrocarbon diluent. In such case, the diluent may be considered as a part of the oil undergoing treatment.

The oil from storage tank it may be withdrawn through pipe M to mixer l2, where it is admixed with benzene from storage tank l3, pipe I and pipe l5, and dichlorethyl ether from tank I6, pipe H and pipe 85. We prefer to use about two and one-half parts of dichlorethyl ether to one part of oil and enough benzene to keep the oil in solution at the dewaxing temperature. These ingredients are thoroughly mixedv in mixer i2 and introduced by pipe it to chiller H. The chiller may contain any suitable heat exchange cooling apparatus such as coil Ma, and it may be provided with suitable scrapers for removing the deposited waxfrom cool surfaces. 0n the other hand, the refrigeration may be accomplished by the vaporization of a diluent or refrigerant directly from the liquid in the chamber. The cooling rate may be about 5 per hour, if ordinary brine cooling coils are used, but if the refrigeration is accomplished by the direct vaporization of propane or equivalent means it may be as high as two or three degrees per minute.

The slurry from the chill chamber is introduced by pipe 20 to a suitable wax filter 2i, wax cake being removed therefrom through enlarged conduit 22 and the filtrate being withdrawn through pipe 23 to collecting tank 24. The filter may be of any desired type, but we preferably use a plurality of vertical filters of the type disclosed in U. S. Patent No. 869,372. While a cake is being built up in one filter the cake in another filter will be washed, and the cake in a third filter will be removed. This particular feature forms no part of the present invention and. it

will not be described in detail.

Dewaxed oil, together with the benzene and dlchlorethyl ether, is introduced from the filtrate collector 24 through pipe 25 and heat exchanger 26 to benzene still 21, which is heated by suitable steam coil 28. The benzene vapors are removed through pipe 29, condensed in condenser 30 and returned to storage tank 03. The hot mixture of dichlorethy] ether and oil is removed from the base of the benzene still through pipe 3i, and it is cooled in exchanger 26 to about 40 F., at which temperature it is introduced into extraction tank 32. At this temperature the paraflinic components of the oil are insoluble in the dichlorethyl ether, and these two liquids may be separated by decantation, centrifuging or other suit= able mechanical means. For instance, the paraffinic oil may be withdrawn from the top of the ether solution through one of the pipes and header 3t,the dichlorethyl ether solution being withdrawn through pipe and heat exchanger 36 to dichlorethyl ether still 37. The liquid in this still is heated by steam coil the solvent being returned through pipe and condenser it to storage tank is, and the naphthenic @611" stituents of the oils being withdrawn through pipe ll and heat exchanger Using 30% dichlorethyl ether and 70% henacne, and using about 3 parts of the oil to "3 parts or" this diluent at a dewaxing temperature of 0 P, we obtained good wax separation and good filter rates. In this case, however, it was found desirable to add further amounts of the dichlor ethyl ether prior to the extraction step, or to repeat the extraction with one or more additional dumps of dichlorethyl ether.

it should be understood that we may use other chlorinated oxygen-containing compounds, particularly chlorinated ethers, instead of 33 dichlorethyl ether, in practicing our invention, and we may use other blending or miscibility agents than benzene, such as acetone, toluene, etc. Of course, if a blending agent, such as toluene or xylene, is used which has approximately the same boiling point as the dichlorethyl ether, it will be necessary to remove all of the diluent from the oil prior to the extraction of the naphthenic constituents. We therefore prefer to use a lower boiling blending agent, such as benzene, so that it may be fractionally removed from the diluted oil prior to the extraction step. A. preferred mixture is 30% dichlorethyl ether and 70% benzene. Filter rates may be increased by the use oi other oliluents, such as light hydrocarbons like butane or propane, and, if necessary, filter aids such as infusorial or diatomaceous earth may be employed.

It should be understood that the amount of clichlorethyl ether, blending agent and/or other cliluents may be varied throughout a relatively large range, depending upon the specific oil which is to undergo treatment. The blending agent may be omitted entirely and the wax may be separated from the diluted oil in liquid form by decantation or in solid form by filtration or centrifuging. lit may be readily ascertained by experiment just how much benzene is required to hold the oil in solution at any given tempera= ture and at the same time heaping the wax out of solution.

While we have described in detail a preferred embodiment of our invention it is to be understood that we do not limit ourselves thereto except as defined by thefollowing claims, which should be construed as broadly as the prior art will permit.

We claim:

1. The method of dewaxing a wax-bearing lubricating oil which comprises intimately admixing said oil with dichlorethyl ether, cooling said mixture to eiTect separation of wax from the oildichlorethyl ether mixture, mechanically removing said wax from said mixture, and removing the dichlorethyl ether from the dewaxed oil.

2. The method of dewaxing lubricating oil which comprises diluting said oil with a mixture of dichlorethyl ether and a non-parafiinic blending agent in such proportion to each other and to the oil that at diluting temperature both oil arouses and wax are soluble in the solvent mixture and that at dewaxing temperature the wax is substantially insoluble and the oil is completely soluble, cooling the mixture to crystallize the wax, mechanically removing the diluted oil from the crystallized wax and removing the blending agent and dichlorethyl ether from said 'dewaxed oil.

3. The combination of claim 2 wherein the blending agent is benzene.

i. in the process of separating petroleum oils into fractions of difierent degrees of parafiinicity by means of the selective solvent action of dichlorcthyl ether, the method of regulating the amount of oil which can be dissolved in the dichlorethyl ether at low temperatures, which comprises mixing said oil and dichlorethyi ether with a non-paramnic blending agent in which the oil is soluble at dewaxing temperatures.

5. The method of claim i wherein the blending agent is benzol.

6. The method of refining a wax-hearing petroleum oil comprising both naphthenic and parafilnic components, which comprises diluting said. oil with dichlorethyl ether and a non-paraihnic blending agent in. which the oil is soluble at dewaxing temperatures, chilling the mixture to erfect solidification of the wax, mechanically separating the solidified wax from the diluted oil, effecting phase separation between paraffinic and naphthenic components of the wax-free (iiluted oil by removing at least a part of the blending agent and subsequently cooling to efiect the separation of a parafilnic phase from a naphthenic phase, removing one phase from the other, 1

and finally removing the dichlorethyl ether and blending agent from both the paraidnic and naphthenic components.

'7. The method of refining a wax bearing petroleum oil comprising both naphthenic and parainnic components, which comprises diluting said oil with dichlorethyl ether and non=-parafdnic blending agent in which the oil is soluble at de waxing temperatures, chilling the mixture to effect solidification of the wax, mechanically sep arating the solidified wax from the diluted oil, heating said diluted oil to remove at least a portion of the blending agent, chilling the heated oil to effect a separation of naphthenic from para-Ethic components of the oil, removing the paranlnic from the naphthenic components, and finally removing the dichlcrethyl ether from both components.

8. The method oi claim lwhere'ln the blending agent is benzol.

9. The method oi claim 7 wherein the diluent which has been heated to remove at least a portion of the blending agent is cooled for the phase separation by indirect heat exchange with cold diluted oil from the wax separation step.

10. The method of claim 1 wherein the waxbearing lubricating oil is diluted with a paraflinic diluent during the wax separation and the wax removal steps.

11. The method of claim 2 wherein the oil is admixed with a light nonviscous parafilnic diluout during the wax crystallization and wax removal steps.

12. The method of claim 1 wherein the lubricating oil contains paraii'lnic and naphthenic components as well as wax and wherein the paraffinlc components are separated from said naphthenic COTY'YW" nts bv said dichlorethyl ether.

13. The method of claim 2 wherein the lubricating oil contains parafflnic and naphthenic comaround 0 F. the mixture has substantially com I plete solvent action on the oil, and substantially no solvent action on the wax, chilling the mixture to precipitate wax constituents of the oil, removing the wax thus precipitated, removing from the resulting dewaxed mixture a suitable portion of the modifying solvent to thereby render the re-. maining solvent liquid selective as between constituents of the oil of diii'ering viscosity index, and

separating from the remaining mixture 9. fraction of desired viscosity index and low pour test.

15. A process of dewaxing oils. which'comprises 1o incorporating with the oil beta beta-dichlorodiethyl ether, chilling, and separating the wax.

CLIFFORD C. BUCHLER. JAMES M. PAGE, JR. 

